From 57143660a0b8014df6ba679762e3d8c54165bda7 Mon Sep 17 00:00:00 2001
From: mariovagomarzal <mariovagomarzal@gmail.com>
Date: Tue, 24 Mar 2026 20:22:41 +0100
Subject: [PATCH] bibtool: fix build with GCC >= 14

bibtool uses K&R-style function definitions, which GCC 14 no longer
accepts by default. Compile with -std=gnu89 as a workaround until
upstream merges https://github.com/ge-ne/bibtool/pull/96.
---
 pkgs/by-name/bi/bibtool/package.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/by-name/bi/bibtool/package.nix b/pkgs/by-name/bi/bibtool/package.nix
index 0c0bdf12b2fc..c8f8be66dd6c 100644
--- a/pkgs/by-name/bi/bibtool/package.nix
+++ b/pkgs/by-name/bi/bibtool/package.nix
@@ -17,6 +17,10 @@ stdenv.mkDerivation (finalAttrs: {
   # Perl for running test suite.
   buildInputs = [ perl ];
 
+  # Uses K&R function definitions, which are not supported by GCC >= 14.
+  # https://github.com/ge-ne/bibtool/pull/96
+  env.NIX_CFLAGS_COMPILE = "-std=gnu89";
+
   installTargets = [
     "install"
     "install.man"